MAMEWorld Forums - EmuChat - Graphics glitches in "Street Fighter II

I was playing around with my "Street Fighter II" boards and I noticed that the graphics sometimes flicker. Sometimes, tiles of the fighters' sprites are just missing, sometimes they are completely dislocated.

Here's a picture of the screen with the game run on original hardware:

At first I thought that my board might be faulty. But the same result happened with another SF2 board and another CPS-1 board.

Now, I tried it in MAME:

Looks like it's not hardware-related at all, but an actual programming bug in "Street Fighter II" itself.

The situation happens quite reliably when you fight Ryu vs. Ken in Chun Li's stage and let the time run out.
(I haven't tested other stages and other fighters, but I remember that in the past, a vase in Dhalsim's stage disappeared a few times.)

The flickering appears only if you press a button while the points are counted (which accelerates the score count and the scene in general). If you don't press anything during that time, the flickering doesn't happen.

Now my question: Does anybody know the technical reason for this? Why do sprite tiles disappear randomly?

By the way, it's not only the fighters. Once, half of the stone was dislocated as well in certain frames.